26-year-old Sean Cole was killed by a croc in the Mary River Wilderness Retreat in Australia

A 26-year-old man was killed on Saturday in the Mary River Wilderness Retreat in Australia, as a crocodile bit him and dragged him underwater.

''This river has the highest density of saltwater crocodiles in the world,'' Senior Sergeant Geoff Bahnert at Darwin police describes.

The Sydney Morning Herald reports how two men attended a friend's 30th birthday and dived in the lake. They were specifically warned about the dangers of getting in the water.

''When you get here, you are told there are crocs, that the river is full of them. Don't swim. Stay at least five meters (16 feet) back from the river. If people follow that advice, it is entirely safe. We have never had an attack before this,'' resort manager Erin Bayard informs.

The lake is located 110 km (68.4 miles) southeast of the Northern Territory capital city of Darwin, The Record writes.

The victim, Sean Cole, and the second man swam across the river, and the attack took place when they tried to cross back. Police believe that their decision to jump in has been influenced by alcohol consumption.

"The advice to tourists is to come, look, take photographs and stay out of the water.

"Several of the group in the party witnessed the male being taken in the jaws of the croc for a period of time, and then he was out of sight," Bahnert says.

Authorities dragged the river and shot a crocodile that was dangerously close to the search party.

"The Mary River is known worldwide to have the greatest saturation of adult saltwater crocodiles in the world. You don't swim in the Mary River," Bahnert adds.

The remains of the missing man are yet to be found. His family drove to the location from the town of Katherine, four hours away.

"Our thoughts are with the family during this very difficult time," said search and rescue co-ordinator, Senior Constable Wade Rodgers.